1. Field of the Invention
The present invention relates to the field of underskin radiation therapy. More particularly, the invention relates to power regulated laser underskin or vein therapy.
2. Information Disclosure Statement
Automatic power or wavelength control is known and is utilized in various forms in a variety of laser applications. Such known devices use a variety of parameters by which to control laser energy. It is often advantageous to provide means for regulating radiation parameters, such as power or pulse rate, to ensure a consistent application of radiation or to provide means for altering parameters in response to changing treatment conditions. Inability to properly regulate output power or pulse rate can compromise the safety of a radiation treatment by increasing the risk of perforation, scarring or skin color changes due to energy overdose. Without proper power regulation, the risk also exists of providing insufficient energy, thus insufficiently treating an area and producing the possibility for the need for additional treatments.
Generally, a feedback mechanism is employed that feeds information regarding the treatment site to a controlling unit, which can then adjust the power, frequency or other characteristics of the laser to provide optimal effects. Such feedback information includes measurements of reflected beams, temperature of probes or fibers and temperature of treated or surrounding tissue. Some feedback systems are in place in order to provide constant unchanging radiation parameters, whereas others modify the delivered radiation to maximize therapeutic effect.
For example, U.S. Pat. No. 6,074,382 by Asah et al. discloses an apparatus for ablating epidermal tissue in cosmetic treatments comprising a beam controller and a detector for detecting at least one tissue characteristic (temperature, texture, elasticity, size and shape). The beam controller will alter the beam characteristics based on feedback provided by the detector as to the type of tissue detected. For example, the handpiece may detect color, and the controller may be programmed to only activate a laser over skin marks such as liver spots to avoid ablating healthy tissue. Another example features a second laser beam to relay tissue characteristics to the handpiece to determine whether the tissue should be ablated. This invention is limited to ablative skin resurfacing, and is primarily a scanning apparatus.
Another patent that uses a tissue parameter as a criteria is U.S. Pat. No. 5,531,740 by Black which externally irradiates malformed veins. A detector detects the different color of the veins to restrict radiation to the veins. Reflected light travels from the treatment area to the apparatus, which only allows emission of radiation when the beam is over an area with a predetermined color. This invention involves external scanning over a treatment area and turning the laser on and off to ensure that only veins are treated.
U.S. Pat. No. 6,231,568 by Loeb at al. describes a device and method for forming a channel in heart tissue using both mechanical and laser energy. A needle is used to penetrate the flesh, and a fiber extends further from the needle, followed by irradiation to vaporize tissue and form a channel in the tissue. A device sends position signals to a control apparatus, which indicates when the needle and/or fiber tip has traveled to a predetermined depth. Different energy delivery rates can be selected, but the delivery rate appears to be constant during treatment, and does not vary with position.
U.S. Pat. No. 6,135,996 by Kolesa et al. describes a controlled advancement laser ablation device to be used in performing transmyocardial revascularization (TMR) and angioplasty. In ablation procedures such as TMR, the rate of advancement of the laser fiber is very important yet difficult to control with hand advanced techniques. Kolesa provides a device for automatically controlling the rate of advancement. In this device, the rate of advancement is determined prior to treatment. Devices are also disclosed that limit the depth to which a fiber can travel. This invention is limited to ablation devices and provides a device that features a predetermined power level and advancement speed.
U.S. Pat. No. 6,176,854 by Cone discloses a device and method for underskin treatments utilizing a laser source and optical fiber for the treatment of a variety of skin conditions or for vein treatment. This method does not provide a method of insertion, and does not provide a way to automatically control the laser output depending on the position of the fiber tip. Additionally, power must be manually regulated.
U.S. Pat. No. 4,846,171 by Kauphusman et al. describes an apparatus for advancing and retracting a fiber within a catheter lumen and for controlling energy transmission. The fiber is connected to a sliding mechanism that allows the practitioner to expose the fiber tip from the lumen after the lumen is properly located and thus avoids having to expose the fiber tip before treatment. Also described is a switching means to allow energy to be transmitted through the fiber. Featured is a means to prevent energy from traveling through the fiber if the distal end is beyond a certain preselected point to prevent accidental irradiation while the fiber is inside the lumen. This invention is a positionally dependent laser control, and does not contain means to automatically adjust radiation parameters.
Devices exist for automatically controlling laser power that are dependent on temperature and are thus safety features to avoid over heating irradiated tissue. For example, U.S. Pat. No. 5,222,953 by Dowlatshahi describes an interstitial tumor hyperthermia device for inducing coagulation in tissue. To avoid overheating the tissue, a thermocouple measures the heat of the tissue and prevents over-irradiation of the tissue. In a preferred embodiment, the fiber is withdrawn at a rate sufficient to maintain the temperature of the tissue within a certain predetermined range. A motor is connected with the thermocouple so that it will respond and pull the fiber faster if the temperature gets too high or slower if the temperature gets too low.
U.S. Pat. No. 5,733,277 by Pallarito describes a device and method for ablating vascular or arterial material. The device consists of a laser source, an optical fiber, catheter, and a device for coupling and rotating the fiber. A computer is programmed for the proper movement both rotationally and axially of the optical fiber based on measurements of the obstructing material before the procedure.
A device and method is needed for radiation treatment that prevents under- or over-treatment of an area by effectively regulating the power output or pulse rate of a radiation delivery device based on a number of parameters without dependence on an operator. The present invention addresses this need.